Demonstrators marched on Saturday to protest the police killing of a 19-year-old black man in Madison, Wisconsin, an incident that came amid growing scrutiny of law enforcement’s use of lethal force against minorities, the poor and mentally ill.

Chanting “the whole damn system is guilty as hell,” protesters walked from police headquarters in the state capital to the neighborhood where the apparently unarmed victim was shot by police Friday evening, according to social media.

At least 100 people took part in the peaceful protest, Madison police spokesman Officer David Dexheimer said.

The shooting occurred after a police officer responded to calls reporting that a man was dodging cars in traffic and had battered another person, Madison Police Chief Mike Koval told reporters.

The officer followed the suspect into an apartment, was struck in the head and shot the teen, who later died at a local hospital, Koval said. An initial search turned up no gun, but it was too soon to know whether the victim had a weapon, Koval added.

Authorities declined to release the teen’s name, though the Wisconsin State Journal newspaper reported that his friends had identified him as Anthony “Tony” Robinson.

The Wisconsin Department of Justice will oversee the investigation into the shooting instead of local authorities, under a new law that was enacted last year.